Metalloprotease inhibitor compounds

In one of the steps in the synthesis of thienopyridine metalloprotease inhibitors possessing anticancer and antiinflammatory activities, the pyridine ring is constructed by treating (3-(2-thienyl)-D-alanine (274) with formaline in an acidic medium (1998EUP803505, 1999PCT9906410). In particular, this method was used to prepare 6-(R)-amino acid 275 in 91% yield. AT-Cbz-(3-(2-Thienyl)-L-alanine amide 276 was transformed into 4,5,6,7-tetrahydrothienopyridine-(65f)-carboxamide by dimeth-oxymethane in the presence of an acid (1996USP5480887). Compound 277 serves as an intermediate in the synthesis of anti-AIDS drugs. 

VS Patel, ME Dowty, TR Baker, SX Peng, MJ Janusz, YO Taiwo. Utilization of N-in-one and in vivo efficacy data for matrix metalloprotease inhibitors to optimize the compound selection process PharmSci 1, 1998. 

Early work with zinc metalloprotease inhibitors focused on the well-characterized agents captopril ((2S)-l-[(2S)-2-methyl-3-sulfanyl-propanoyl] pyrrolidine-2-carboxylic acid) and phos-phoramidon (/V-alpha-i,-rhamnopyranosyloxy[hydroxyphosphinyl -i,-leucyl-L-tryptophan). These compounds, however, were found to have little inhibitory activity against BoNT (Adler et al., 1994, 1999a). The poor efficacy of captopril was suggested to stem from unfavorable steric constraints in the binding of proline at the active site of BoNT (Schmidt and Stafford, 2002). 

Early work with zinc metalloprotease inhibitors focused on the well-characterized agents captopril and phosphoramidon. These were found to have little or no inhibitory activity against any BoNT serotype. Phosphoramidon analogs in which Leu-Trp was replaced by Phe-Glu to resemble the cleavage site of synaptobrevin exhibited little increase in inhibitory activity one analog was slightly more potent and two were significantly less potent than the parent compound. 

Blocking metabolism needn t always involve direct replacement of an atom at the metabolic site. Electronic effects from substituents at other positions can sometimes do the trick as well. For example, pnra-hydroxylation of a benzene ring can sometimes be curtailed by meta.meta-difluorination. If changing the electronics of a molecule can work, it s a cinch that chemists will try using steric effects as well. The improved rat PK properties of Compound 23, the matrix metalloprotease inhibitor shown in Figure 9.24 (Clp 44 mL min kg ), versus Compound 2, which lacks the a,a-dimethyl group (Clp 86 mL min kg ) were attributed in part to steric hindrance of metabolism of the hydroxamic acid. ... 

Figure 9-11 Application of SAR-by-NMR to the development of a metalloprotease inhibitor. Screening of a library of small organic compounds revealed acetohydroxamic acid and 4-phenylpyrimidine as weakly binding to stromelysin (Kd 17 mM and 20 mM, respectively) at adjacent sites left, the contour lines symbolize the protein surface). After introduction of an appropriate linker (shown in grey, right panel) and systematic structural variations, a highly potent inhibitor of stromelysin and gelatinase A (IC50 = 25 nM, right) could be developed within a few months. [37], [38].

Protease Classification. In order to rationally design an inhibitor for a protease it is first necessary to place it into one of four families of proteases (see Table V). For a new enzyme, a study of its inhibition profile with a series of general protease inhibitors is sufficient to classify it into one of the four families. The inhibitors usually used are diiso-propylphosphofluoridate (DFP) or phenylmethane sulfonyl fluoride (PMSF) for serine proteases, 1,10-phenanthroline for metalloproteases, thiol reagents such as iodoacetate or N-ethylmaleimide for thiol proteases, and pepstatin or diazo compounds such as diazoacetyl-norleucine methyl ester for carboxyl proteases. 

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